What transcoding to use for archival footage?

Hello all,
I am a director who is ready to start making a director cut. All of the footage is from Youtube or other online sources. I am looking for the fastest way to edit. Quality of the footage is not important, we will buy needed footage later in the original format. There are about 15 hours of footage. What transcoding should I use when I import the files? Should I convert it first into .mov?
Will highly appreciate any insights.
Thank you very much in advance.
Lucy

[Lucy Slavinsky]"All of the footage is from Youtube or other online sources. I am looking for the fastest way to edit. Quality of the footage is not important, we will buy needed footage later in the original format. There are about 15 hours of footage. What transcoding should I use when I import the files? "

If this is 1080p or 720p content from Youtube or other online source, IMO you don't need to transcode to proxy or anything else. On a halfway decent machine, e.g. 2012 iMac 27, 2013 MacBook Air, etc, FCPX is fast enough to edit that natively.

You can even import it with "leave files in place" which further accelerates the import and reduces disk consumption. Just make sure neither "optimized media" nor "proxy media" are selected during import and those are also deselected in FCPX preferences>import.

If it is 4k you may need to transcode it to proxy for best editing performance.

However there is no automated way to "match back" clips on a timeline to the original content you plan on later acquiring for the final version. Therefore I suggest you use the Youtube version for a very rough assembly and don't use any effects or transitions. That will be a small fraction of the original 15 hr. Then acquire the original format, and manually replace each clip, after which you can continue the edit, add transitions, effects, correct color/exposure, etc.

OTOH, if you add effects and color/exposure correction to the Youtube version, this could help non-editors better visualize the potential quality. You might be able to cut/paste those effects to the original content, but you never know how different the image and color characteristics will be. So that might not work.

Thank you very much for your response! There is no 4K clips at all, footage is pretty old. So, no need to convert anything to .mov? Conversion increases size dramatically.
I absolutly agree with you - it supposed to be a very rough cut just to show potential stakeholders how the film will look.
Lucy

Thank you. I understand. I am still concerned about using mp4 which is very small in size, comparing to .mov which became pretty big after compression. What would be the advantage to use .mov for a rouph cut which will be replaced completly later on?
Regards,
Lucy